Halide Perovskite Nanocrystal Photocatalysts for CO2 Reduction: Successes and Challenges.

In current research, halide perovskite nanocrystals have emerged as one of the potential materials for light-harvesting and photovoltaic applications. However, because of phase sensitivity, their exploration as photocatalysts in polar mediums is limited. It has been recently reported that these nanocrystals are capable of driving solar-to-chemical production through CO2 reduction. Using bare nanocrystals and also coupling in different supports, several reports on CO2 reduction in low polar mediums were reported, and the mechanism of involved redox processes was also proposed. Considering the importance of this upcoming catalytic activity of perovskites, in this Perspective, details of the developments in the field established to date and supported by several established facts are reported. In addition, some unestablished stories or unsolved pathways surrounding the redox process and the importance of using a polar solvent which confused the understanding of the exclusive roles of perovskite nanocrystals in catalysis are also discussed. Further, the future prospects of these materials that face challenges in dispersing in polar solvents, a key process in redox catalysis for CO2 reduction, are also discussed.